This invention relates to footwear having retractable spikes.
Structures of this type are generally known in the art, as exemplified by the following U.S. Pat. Nos. 3,717,238; 3,747,238; 3,631,614; 2,331,609; 2,776,499; 3,343,283; 3,793,751; 1,179,652; 1,433,660; 2,022,655; 2,920,404.
Of these, U.S. Pat. Nos. 3,717,238 and 3,793,751 show the use of eccentric mechanisms to cause the sole spikes to protrude, and the former patent incorporates spring elements. U.S. Pat. No. 3,343,283 shows the use of a key to extend the spikes. Other patents show structures which could be clamped onto a shoe or boot.
None of these prior art arrangements, however, shows or suggests a structure wherein the spikes are sealed entirely inside a footwear sole that may be permanently secured to shoes and boots, and may be extended and retracted without unsightly external keys, levers or other projections.
Many snow and ice gripping spikes and cleats have been devised to be tied or clamped onto footwear. Other spikes and cleats have been built into footwear, but these require keys or external levers to extend or retract the spikes or cleats, and no thought has been given to keeping water, ice and snow out of the mechanism. These previous arrangements have the inherent problems of where to store the attachments when they are not in use, the discomfort of handling the attachments in cold and snowy weather, the problems of finding the keys, and the problems of manipulating the ties, clamps and levers when they are covered with ice and snow.
Accordingly, an object of the present invention is to provide, for footwear, retractable spikes that are effective when extended and that do not detract from the appearance of the shoe when the spikes are withdrawn.
Another object of the invention is to provide a mechanism for controlling retractable spikes, which mechanism may be completely hidden inside the sole of a shoe.